Built-in to the toilet would be a 4000V power supply (neon sign power supply) whose leads would be connected to two 6"x12" plates of metal mesh. These mesh plates would be glued on alternate sides of a 7"x13" piece of 1/4" thick glass, careful to leave a small amount of space between the glass and metal.
The current would be applied when the flusher is depressed, and would have a 10-second timer. The current would arc thru the glass and be exposed to the air on each side. It lights up with a purple color and has a hissing sound. Vast amounts O3(ozone) would flood the room and infiltrate any foul smelling gases, oxidizing them on contact. The rest of the O3 gas, being unstable, would then recombine back into O2 gas. No harmful effects. Perhaps there would be a 5-minute timer to reset the switch, so people couldn't kill themselves.